Originally Posted by BikeWNC
Terry's right. Except when climbing where a heavier rider must overcome gravity. At the same speed on a hill, the heavier rider will produce more watts, therefore expend more Calories. What typically happens though is at some point the lighter rider will pull away from the heavier rider (if both are equally conditioned) and they will produce the same watts, expend the same calories, but the heavier rider will be slower. Sure, it will take the heavier rider longer to get up the hill and thus he will burn slightly more total Calories on the climb, but it really isn't that much more as a percentage of the total Calories burned on the ride.
And holding himself on the bike, and maintaining balance, and overcoming aerodynamic drag, and steering, etc. And you and Terry are still making the same mistake--you are confusing caloric output(energy needed to propel the bike) with caloric expenditure(energy burned during an activity). They are NOT the same thing. Even if one looks at caloric output alone, there is a significant increase in the energy needed to propel a heavier rider v. a smaller rider. By that logic, a Ford Excursion and a Toyota Prius should have roughly the same gas mileage on the highway, right?